/* Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.activiti.engine.impl.bpmn.helper;

import java.util.List;

import org.activiti.engine.delegate.Expression;
import org.activiti.engine.delegate.VariableScope;
import org.activiti.engine.impl.bpmn.parser.FieldDeclaration;
import org.activiti.engine.impl.cfg.DelegateExpressionFieldInjectionMode;
import org.activiti.engine.impl.context.Context;

/**
 * @author Joram Barrez
 */
public class DelegateExpressionUtil {
  
  public static Object resolveDelegateExpression(Expression expression, VariableScope variableScope) {
    return resolveDelegateExpression(expression, variableScope, null);
  }
  
  public static Object resolveDelegateExpression(Expression expression, 
      VariableScope variableScope, List<FieldDeclaration> fieldDeclarations) {
    
    // Note: we can't cache the result of the expression, because the
    // execution can change: eg. delegateExpression='${mySpringBeanFactory.randomSpringBean()}'
    Object delegate = expression.getValue(variableScope);
    
    if (fieldDeclarations != null && fieldDeclarations.size() > 0) {
      
      DelegateExpressionFieldInjectionMode injectionMode = Context.getProcessEngineConfiguration().getDelegateExpressionFieldInjectionMode();
      if (injectionMode.equals(DelegateExpressionFieldInjectionMode.COMPATIBILITY)) {
        ClassDelegate.applyFieldDeclaration(fieldDeclarations, delegate, true);
      } else if (injectionMode.equals(DelegateExpressionFieldInjectionMode.MIXED)) {
        ClassDelegate.applyFieldDeclaration(fieldDeclarations, delegate, false);
      }
      
    }
    
    return delegate;
  }

}
